Energy Capturing Performance Comparison between Duty-Cycle Control and Current Control for Photovoltaic System

In this paper, energy capturing performance of Duty-cycle control and current control method are compared in the photovoltaic (PV) system under the same operating points and verified by simulation and experiment. Maximum power point tracking (MPPT) algorithm is based on the perturb and observe (P&O) algorithm which has advantages of simple implementation, controllable availability and fast response. As a precondition for the performance comparison between two control methods, the same variable width of the PV voltage is used for every cycle of MPPT execution by adjusting the variation of width of Duty-cycle reference to be equalized to the variation width of current reference. To compare and verify the performance of two control methods, simulations and experiments are carried out to compare PV voltage, PV current and captured energy in PV Power Conditioning System(PCS). Under the same operating points of the PV curve, two control methods generate the same magnitude of captured energy during a cycle of MPPT execution. For instance, captured energy for a cycle is 3.26[kWs] for Duty-cycle control and 3.22[kWs] for current control in experimental results.